FIELD OF INVENTION
The invention relates to an automatic scraping device and method to clear the
surface of segregation plate of a sinter plant.
BACKGROUND OF THE INVENTION
Sintering is a process in a steel plant, whereby a green mix of iron ore particles,
fluxes (such as limestone dolomite and serpenine), fuel and plant fines (such as
mill scale, blast furnace dust and returned sinter fines) are converted into a
agglomerate called sinter.
The rotating mixer drum discharges green mix on the sinter bed. White
discharging it is made to fall on the segregation plate for uniformity of
distribution of granules on the sinter bed. The granules has tendency to stick on
the surface of segregation plate. The sticking is so severe that the normal flow is
disturbed and the operator is required to shake the cover sheet placed on
segregation plate vigorously and make multiple striking with the rod to remove
the stick portions. This process is cumbersome and time consuming and requires
a separate cover sheet on the segregation plate for manual operation.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an automatic scraping device
and method to clean the surface of segregation plate of sinter plant which
eliminates the disadvantages of prior art.

Another object of invention is to remove the cover sheet placed on the
segregation plate for clearing the sticking of green mix.
Another object of the invention is to propose an automatic scraping device and
method to clean the surface of segregation plate of sinter plant which ensures a
smooth flow of a green mixture of non ore, fluxes and fuel on the sinter bed.
A still another object of the invention is to propose an automatic scraping device
and method to clean the surface of segregation plate of sinter plant which
prevents the sticking of material on the segregation plate.
A further object of the invention is to propose an automatic scraping device and
method to clean the surface of segregation plate of sinter plant which is capable
of performing without manual intervention.
A still further object of the invention is to propose an automatic scraping device
and method to clean the surface of segregation plate of sinter plant which results
saving of process time.
SUMMARY OF THE INVENTION
Accordingly there is provided an automatic scraping device (A) and method to
clean the surface of a segregation plate (1) in a sinter plant. A driving unit of
geared motor (6) and chain and sprocket assembly (4) moves the autoscraper
arm (2) from one end to the other end of the segregation plate (1). The
autoscraper consists of a carriage (3) fixed with a plurality of scraping arms (2).
The carriage (3) is connected to the scraping arms (2) through links (as shown in
figure 2) with pin bush joint. The scraper arm is made to remain in contact with
the segregation plate by tie rod arrangement (8&9). The device is actuated in
auto as well as manual modes. The sequence of operation is controlled by

input/output sequence control through PLC software. The whole process is
governed by cables and accessories which are connected to the power circuit.
The autoscraper is a straight line scraper which moves a plurality of scraping
arms (2) which covers the entire surface area of the segregation plate (2) and
thus dean the plate.
Fig.1
A - shows a line diagram of autoscraping unit.
B - shows green mixture dropping on the segregation plate through hopper.
Fig. 2 - shows a side view of the same unit.
INVENTION
As shown in Fig.l and 2, an autoscraper (A) is an automatic device capable of
moving along the segregation plate to clean the surface. The autoscraper is a
completely automatic straight line scraper. It removes the material from the
segregation plate (1) surface by moving for example two scraping arms (2) in
both to and fro directions. After reaching at its extreme end position geared
motor (6) automatically reverses its directions. The automatic systems comprises
of the following devices:

(i) Automatic Scraper:- It has for example two scraping arms (2) made
of for example mild steel plates with ceramic lining on their bottom to reduce
wear and tear of blade material. They are mounted on a carriage (3). This
carriage (3) is connected by duplex chain (5) passing over two sprockets (4)
driven by a geared motor (6). These sprockets (4) are mounted on the
extreme end position of guide rail. The carriage assembly of carriage (3) and
scraping arms (2) consist of a fabricated steel carriage (3) with the
replaceable scraping arms (2) and four pre-lubricatedand sealed ball bearing
wheels. The scraping arms (2) are fixed on the carriage (3) bracket moving
on the guide rail. The carriage (3) is connected to the motor (6) through link
(9) stud (8) and clevis (7).
(ii) Driving Device
The autoscraper is driven by a three phase AC geared motor (6) with an
output speed for example of 0.83 rpm. It is designed and constructed to
withstand the stresses and shock loads of impact during entering and leaving
of the falling stream of green mixture.
It also consists of two proximity switches and two limit switches and the cable
connection to the terminal. All these units are covered by a fabricated cover
which stops the dust from entering the devices.
(iii) Guide Rail:
The guide rail is provided in three units. Left and right guide rails are of similar
type while the central rail differ in dimension with them. The left, central and
right rail make one unit after assembly. The carriage (3) containing the Wades
(2) passes over them. The carriage (3) holding the blades are fixed with four
wheels mounted on the guide rail. The wheel facilitates smooth to and fro
movement of blades along the guide rail. In order to stop the possibility of

derailment four wheels have been provided in both the planes at perpendicular
to each other.
(iv) Operator's interface:
Autoscraper is designed to scrape the entire surface of segregation plate (1) by
moving its two arms (2) in to and fro motion. It stops sticking of green mix on
the surface of segregation plate. It has a provision of auto and manual modes of
operation. For that, a two position selector switch is provided at the main control
desk at main control room. Two positions are 'interlock' and 'delock' respectively.
The operator has to put the selector switch at 'interlock mode for the automatic
operation of the autoscraper. It continues to move in one direction until it
reaches the set position of proximity switch. After reaching that: point the motion
stops and reverses till it reaches home position as per command from PLC. The
movement of scraping arms (2) can be varied by programming PLC as per the
requirement of operator. In case of any unwanted situation and to carry out
maintenance job, the operator has the liberty of putting it into 'Delock' mode. In
that case he has to go near the machine to operate the scraper by pressing the
push buttom switches provided at the local control post.
(vi) Input/Output — Sequence Control
The PLC software examines the healthiness of different inputs associated with
the system. It examines the electrical status as follows:
1) Healthiness of electrical drive unit
2) Emergency stop push button not pressed
3) Status of the selector switch at interlock mode
4) Running status of sinter machine
5) Home position limit switch is activated
6) Is the stipulated time elapsed since last cycle of scraping?

7) Extreme limit-Switch of either side is not cut.
If all the above conditions are healthy,it satisfies the logic and sequence to
generate the output command for running the scraper in auto mode. The
scraper completes one cycle operation of scraping, stops there at home
position and waits there till the command for next cycle comes. It takes about
4 to 5 minutes to complete one cycle of to and fro motion. In case of any
abnormality the operator at the control room will get audible-alarm with
message text.
(Vi) System cabling and accessories:-
The system is connected to the power circuit through for example three core
4 sq. mm. cable for motor power.
Apart from that it is also connected to the PLC through for example 1.5 sq.
mm. Cable for different output/inputs namely emergency stop, start and stop
push button, home position limit switch.The selector switch at the main
control desk is connected to the PLC through for example 1:5 sq.mm cable.
All these accessaries are the integrated parts of the autoscraper.

WE CLAIM:
1. An automatic scraping device to clean the surface of a segregation
plate comprising:
at least one carriage (3) carrying a plurality of scraping arms (2); said
carriage is fixed to at least one sprocket chain assembly (4);
said carriage is mounted on a plurality of guide rails being made into one
unit;
a plurality of wheels fixed with the carriage (3) being mounted on the
guide rail characterized in that the scraping device cleans the segregation
plate automatically without manual intervention.
2. An automatic scraping device as claimed in claim 1, wherein the
scraping arms (2) are made of mild steel plates.
3. An automatic scraping device as claimed in claim 1, wherein the
scraping arms (2) are provided with ceramic lining at their bottom.
4. An automatic scraping device as claimed in claim 1, wherein the
carriage (3) is made of fabricated steel structures.
5. An automatic scraping device as claimed in claim 1, wherein the
sprocket chain assembly (4) is driven by a geared motor (6).
6. An automatic scraping device as claimed in claim 1, wherein the
wheels are fixed in both planes perpendicular to each other.

7. An automatic scraping method to clean the surface of a segregation
plate (1) comprising:
atleast one carriage (3) carrying a plurality of scraping arms (2)moves
on guide rails;
geared motor (6) drives the carriage (3) being fixed with chain-
sprocket assembly (4);
a plurality of wheels being fixed with the carriage (3) and mounted on
guide rail provide smooth to and fro movement of scraping arms (2).

An automatic scraping device (A) and method to clean the surface of a
segregation plate (1) of a sinter plant consists of a carriage (3) carrying a
plurality of scraping arms (2) wherein the carriage is fixed to a chain and
sprocket (4) assembly. The carriage (3) being mounted on guide rails moves the
scraping arms (2) throughout the length of the segregation plate (1). A plurality
of wheels being fixed with the carriage (3) are mounted on the guide rails. A
geared motor (6) drives the carriage which is fixed with chain and sprocket
assembly (4).